1. Field of the Invention
The present invention relates to Functional Electrical Stimulation Systems.
2. Background Information
Functional Electrical Stimulation (FES) systems artificially stimulate the muscles, and muscle groups, of persons through the use of electrical current in order to stimulate movement. As early as 1971 Liberson applied electrical stimulation to assist walking in patients with foot drop. Current FES systems are mainly designed for persons after a spinal cord injury and stroke.
Several different groups of researchers have designed implant electrodes and systems for spinal cord injured persons. These systems need to be surgically implanted into muscle groups and are aimed at control of deep muscles.
After stroke patients often suffer from weakness in the extensor muscle on the upper limb and involuntary muscular contractions due to spasticity of the flexor muscle groups. FES can be used with stroke victims to stimulate the extensor muscle to open the hand and reduce the spasticity. FES can be used for therapeutic training and some patients have been found to partially or completely recover hand functions. Therefore. it is not necessary to have the implant system.